Warsaw's restaurants and food stores

Hello,
I am new to Warsaw. and I am doing my internship there so I need some help
I have a lot of problem with my digestion so I am pescaterian as in Polish is Pescowegetarianizm ( like vegetarian but eat seafood). and I work in Warsaw Trade Center. I need to find some restaurants/ food stores near this building which offer any seafood/ veggie dishes. I saw like a Pizza place and 2 sushi places. I do love sushi but not willing to eat them everyday. Could anyone help me with some suggestion?

And also, if anyone know is there any place that sells Chia seeds and some healthy food with reasonable price?

Thank you so much